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Message-ID: <20240625125803.38038-2-tursulin@igalia.com>
Date: Tue, 25 Jun 2024 13:58:02 +0100
From: Tvrtko Ursulin <tursulin@...lia.com>
To: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org,
kernel-dev@...lia.com,
Maíra Canal <mcanal@...lia.com>,
Tvrtko Ursulin <tvrtko.ursulin@...lia.com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH 1/2] numa: Add simple generic NUMA emulation
From: Maíra Canal <mcanal@...lia.com>
Add some common code for splitting the memory into N emulated NUMA memory
nodes.
Individual architecture can then enable selecting this option and use the
existing numa=fake=<N> kernel argument to enable it.
Memory is always split into equally sized chunks.
Signed-off-by: Maíra Canal <mcanal@...lia.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@...lia.com>
Co-developed-by: Tvrtko Ursulin <tvrtko.ursulin@...lia.com>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: “Rafael J. Wysocki" <rafael@...nel.org>
---
drivers/base/Kconfig | 7 ++++
drivers/base/Makefile | 1 +
drivers/base/arch_numa.c | 6 ++++
drivers/base/numa_emulation.c | 67 +++++++++++++++++++++++++++++++++++
drivers/base/numa_emulation.h | 21 +++++++++++
5 files changed, 102 insertions(+)
create mode 100644 drivers/base/numa_emulation.c
create mode 100644 drivers/base/numa_emulation.h
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 2b8fd6bb7da0..1f60cd4dd057 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -230,6 +230,13 @@ config GENERIC_ARCH_NUMA
Enable support for generic NUMA implementation. Currently, RISC-V
and ARM64 use it.
+config GENERIC_ARCH_NUMA_EMULATION
+ bool
+ depends on GENERIC_ARCH_NUMA
+ help
+ Enable NUMA emulation. Note that NUMA emulation will only be used if
+ the machine has no NUMA node.
+
config FW_DEVLINK_SYNC_STATE_TIMEOUT
bool "sync_state() behavior defaults to timeout instead of strict"
help
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 3079bfe53d04..34fcf5bd7370 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
obj-$(CONFIG_GENERIC_MSI_IRQ) += platform-msi.o
obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o
obj-$(CONFIG_GENERIC_ARCH_NUMA) += arch_numa.o
+obj-$(CONFIG_GENERIC_ARCH_NUMA_EMULATION) += numa_emulation.o
obj-$(CONFIG_ACPI) += physical_location.o
obj-y += test/
diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c
index 5b59d133b6af..6ad08f681b3c 100644
--- a/drivers/base/arch_numa.c
+++ b/drivers/base/arch_numa.c
@@ -15,6 +15,8 @@
#include <asm/sections.h>
+#include "numa_emulation.h"
+
struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
EXPORT_SYMBOL(node_data);
nodemask_t numa_nodes_parsed __initdata;
@@ -30,6 +32,8 @@ static __init int numa_parse_early_param(char *opt)
return -EINVAL;
if (str_has_prefix(opt, "off"))
numa_off = true;
+ if (str_has_prefix(opt, "fake="))
+ return numa_emu_cmdline(opt + 5);
return 0;
}
@@ -471,6 +475,8 @@ void __init arch_numa_init(void)
return;
if (acpi_disabled && !numa_init(of_numa_init))
return;
+ if (!numa_init(numa_emu_init))
+ return;
}
numa_init(dummy_numa_init);
diff --git a/drivers/base/numa_emulation.c b/drivers/base/numa_emulation.c
new file mode 100644
index 000000000000..df652fa8351b
--- /dev/null
+++ b/drivers/base/numa_emulation.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Simple NUMA emulation.
+ *
+ * Copyright © 2024 Raspberry Pi Ltd
+ *
+ * Author: Maíra Canal <mcanal@...lia.com>
+ * Author: Tvrtko Ursulin <tursulin@...lia.com>
+ */
+#include <linux/memblock.h>
+
+#include "numa_emulation.h"
+
+static unsigned int emu_nodes;
+
+int __init numa_emu_cmdline(char *str)
+{
+ int ret;
+
+ ret = kstrtouint(str, 10, &emu_nodes);
+ if (ret)
+ return ret;
+
+ if (emu_nodes > MAX_NUMNODES) {
+ pr_notice("numa=fake=%u too large, reducing to %u\n",
+ emu_nodes, MAX_NUMNODES);
+ emu_nodes = MAX_NUMNODES;
+ }
+
+ return 0;
+}
+
+int __init numa_emu_init(void)
+{
+ phys_addr_t start, end;
+ unsigned long size;
+ unsigned int i;
+ int ret;
+
+ if (!emu_nodes)
+ return -EINVAL;
+
+ start = memblock_start_of_DRAM();
+ end = memblock_end_of_DRAM() - 1;
+
+ size = DIV_ROUND_DOWN_ULL(end - start + 1, emu_nodes);
+ size = PAGE_ALIGN_DOWN(size);
+
+ for (i = 0; i < emu_nodes; i++) {
+ u64 s, e;
+
+ s = start + i * size;
+ e = s + size - 1;
+
+ if (i == (emu_nodes - 1) && e != end)
+ e = end;
+
+ pr_info("Faking a node at [mem %pap-%pap]\n", &s, &e);
+ ret = numa_add_memblk(i, s, e + 1);
+ if (ret) {
+ pr_err("Failed to add fake NUMA node %d!\n", i);
+ break;
+ }
+ }
+
+ return ret;
+}
diff --git a/drivers/base/numa_emulation.h b/drivers/base/numa_emulation.h
new file mode 100644
index 000000000000..62b38215a2f0
--- /dev/null
+++ b/drivers/base/numa_emulation.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * NUMA emulation header
+ *
+ * Copyright © 2024 Raspberry Pi Ltd
+ */
+
+#ifdef CONFIG_GENERIC_ARCH_NUMA_EMULATION
+int numa_emu_cmdline(char *str);
+int __init numa_emu_init(void);
+#else
+static inline int numa_emu_cmdline(char *str)
+{
+ return -EINVAL;
+}
+
+static int __init numa_emu_init(void)
+{
+ return -EOPNOTSUPP;
+}
+#endif /* CONFIG_NUMA_EMU */
--
2.44.0
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